What is Jadeite?

Jadeite can be composed of Jadeite Jade/OmphaciteJade/ Kosmochlor Jade. This is also known as Fei Chui. 

Fei Cui is a granular to fibrous polycrystalline aggregate, which is composed solely, or principally of any of the following or any combination of the following: Jadeite, Omphacite and Kosmochlor.

Fei Cui, Jadeite Jade is a granular to fibrous polycrystalline aggregate. Its major mineral component is Jadeite (NaAlSi2O6). Other minerals such as Omphacite and Kosmochlor may also be present.

Fei Cui, Omphacite Jade is a microgranular to microfibrous polycrystalline aggregate. Its major mineral component is Omphacite [(Ca,Na)(Mg,Al)Si2O6]. Other minerals such as Jadeite and Kosmochlor may also be present.

Fei Cui, Kosmochlor Jade is a granular to fibrous polycrystalline aggregate. Its major mineral component is Kosmochlor (NaCrSi2O6) . Other minerals such as Jadeite and Omphacite may also be present.

When there is a need to differentiate of the three Fei Cui members : Jadeite Jade, Omphacite Jade and Kosmochlor Jade. 

 

Major Physical Properties of FeiCui-Jadeite Jade / Omphacite Jade / Kosmochlor Jade

Jadeite Jade Omphacite Jade Kosmochlor Jade
Texture Polycrystalline, uneven granular
to fibrous interlocking texture		 Polycrystalline, uneven, fibrous to
granular interlocking texture		 Polycrystalline, uneven, granular
to fibrous interlocking texture
Common Color Colourless, white and green,
yellow, reddish orange, brown,
grey, black, light purplish red,
violet, blue and pink etc.		 Green to black and bluish green
in reflected light; Green to
dark green and bluish green in
transmitted light; usually even		 Intense bright green to dark green
to black; usually uneven
Transparency Transparent to opaque Transparent to opaque Transparent to opaque
Luster Vitreous to greasy
The polycrystalline crystal
aggregate may show some
glistening on the surface (due to
Jadeite’s two directions of perfect
cleavages)		 Vitreous, due to fine-grained
texture, and smooth polished
surface		 Vitreous to dull vitreous, due to
coarse-grained texture and rough
polished surface
Mohs’ Hardness 6.5 – 7 7 5, 5-6 Brittle
Specific Gravity 3.25-3.40 3.30-3.45 (Usually slightly higher than Jadeite Jade) 3.35-3.50 (Usually higher than Jadeite Jade)
Optical Nature Anisotropic (polycrystalline aggregate) Anisotropic (polycrystalline aggregate) Anisotropic (polycrystalline aggregate)
Refractive Index 1.65 – 1.67 (± 0.01), by spot reading method (distance vision method) normally read as 1.66 1.67 - 1.68 (± 0.01), by spot reading method (distance vision method) normally read as 1.67 (slightly higher than Jadeite Jade) 1.68 - 1.72 (± 0.01), by spot reading method (distance vision method) normally read as 1.72 (higher than Jadeite Jade and Omphacite Jade)
Ultraviolet Fluorescence None to faint Inert Inert
Absorption Spectrum Fe absorption band may appear at 437nm; Cr absorption line(s) approximately at 630 nm, 660nm and 690 nm may be observed on bright green Jadeite Jade. Fe absorption band may appear at 437nm as Jadeite Jade; Cr absorption line(s) may be observed in the red at 630nm, 660nm and 690nm Cr absorption lines may appear in the red at 630nm, 660nm and 690nm; Fe absorption band may appear at 437nm